Yep repairing class D just takes a bit of understanding of the circuits, but most can be repaired no problems, class D car amps have been around for over 20 years at least now and have been repairable since day one. Any reputable amp repair place will repair class D and is likely the bread and butter for them, with perhaps a few exclusions on what they work on. The exceptions are the ones that MOSFETs have been discontinued on or other unusual components and finding a replacement that functions properly may be difficult to near impossible. This is mainly older amps 15-20+ years old when parts become obsolete and no longer made, just depends on the design. Can often substitute MOSFETs, but it takes time to do properly and sometimes not worth it unfortunately. Class D can be much more picky about parts than class AB.
I’ll say most amp problems are simply blown output or power supply transistors and a handful of associated parts, meaning you replace this and the amp is back 100% functional, fairly easy, usually. Class A, AB, B, or D, doesn’t make much difference if the repair guy knows what he’s doing.
However, there are those times an amp has deeper problems that are hard to find and it will blow up again on you. But that can happen with any class of amp. And of course if someone blew an amp up once, then sent it in for repair, good chance they are they are going to blow it up again when they get it back.
I think the better question is, is it worth it? Meaning brand / model plays a big role in repairing. If it’s a Rockville or VVME 1500.1 or Pyle, probably not worth the parts / labor unless you hobby DIY at home and just want to repair it. If it is a Sundown, Rockford, JL (insert any other decent brand here), then it is likely worth repairing, Class d or AB makes no difference.